The present invention relates to a coupling device for restraining belts, particularly for children's safety seats used in motor vehicles.
The restraining belts for children's safety seats for motor vehicles are typically constituted by three or five branches, one of which is attached at one of its free ends to the body of a coupling device, or buckle. The other two or four branches are attached at their free ends to respective latching elements, or tongues, adapted to be inserted and locked in the buckle body.
A coupling device of this kind is known for example from European Patent application EP-A-1 295 541.
According to the prior art, the tongues (or the tongue, where a restraining system with only two branches is used) comprise an elongated metal stem, the free end portion of which is variously shaped so as to engage in the buckle body. The stem of the tongue extends from an attachment portion adapted to be connected to the belt and generally made of plastic, in which a slot is provided for connection to the end of the associated branch of the belt. However, such tongues suffer from the drawback that the metal part thereof to be engaged in the buckle body is in view when the belt is not being used and therefore can become warm, especially during hot days and/or when the motor vehicle is exposed to the sun rays, whereby the temperature of the tongue may become dangerously high and could produce burning injuries when contacted particular by children. Moreover, there may be problems of allergies to metals (such as, for example, chrome) which are used in the metal part of the tongue.